The present invention relates to an electric power source breaker which isolates a power supply circuit, for example, by means of rotational movement of a motor, and in particular relates to a power source breaker which can forcedly and surely isolate a power supply circuit in case of something unusual such as short circuiting of a wire harness, collision of road vehicles, and also has a structure suitable for miniaturizing itself.
FIG. 1 is a systematic diagram showing an example for electronic automobile parts to which a conventional power source breaker is applied. As shown in the figure, the electronic automotive part 100 includes a power supply circuit assembled by connecting a battery 101 of an automobile to each load 102-104 disposed at each location of the automobile using a wire harness 106 with electric wires 105, and a power source breaker 107 intervened in the power supply circuit.
When a circuit-cut signal generated at a power source controller 108 is input in case of something unusual such as short circuiting of a wire harness 106 or collision of road vehicles, the power source breaker 107 can stop supplying power from the battery 101 to each load 102-104 etc. through releasing a lock in a manner as described hereinafter according to FIG. 2.
FIG. 2 is a configuration of a solenoid-type power source breaker 107A showing an example of the power source breaker 107 in FIG. 1, and FIG. 2A is a top view and FIG. 2B is a side view. The solenoid-type power source breaker 107A includes a shaft 111, disposed on a base body 110 as shown in FIG. 2A, which is constrained with a lock 113 pressing down the shaft 111 to maintain a terminal 112a and a terminal 112b electrically continued in a connected state, before the circuit-cut signal is input to the solenoid-type power source breaker 107A at the initial state.
At this initial state, electric current in the power supply circuit flows through the rout of the terminal 112a the shaft 111 the terminal 112b , and the terminal 112a and the terminal 112b can supply a large current because of their having the multicontact spring structures.
When the circuit-cut signal is input, by supplying current to a solenoid 115 for drawing a plunger 116 in order to release the lock 113 in a linked state with the shaft 111, pushing forward the shaft 111 by means of pushing force provided by a release spring 114 to make the terminal 112a isolated from the terminal 112b, finally making the terminal 112a electrically open off from the terminal 112b to stop supplying power from the battery 101 to each load 102-104 etc.
However, in the conventional structure shown in FIG.2, once an impulse is applied to the shaft 111 in the axial direction shown as an arrow A in the figure, the plunger 116 of the solenoid 115 is liable to malfunction to draw a lever 118, and the malfunction may result in a problem of releasing the lock 113 out of a linked state with the shaft 111. There has been also a problem that a need of miniaturization cannot have been coped with due to the use of the solenoid 115.
The present invention, in consideration of the situation described above, aims to provide a power source breaker which can forcedly and surely isolate a power supply circuit in case of abnormalities such as short circuiting of a wire harness, collision of road vehicles, and also has a structure suitable for miniaturizing itself.
A power source breaker according to the present invention is such an apparatus that comprises a pair of terminals intervened in a power supply circuit connecting a battery of a road vehicle and each load disposed at each location of the vehicle, and a shaft which can contact with and disconnect from each terminal through sliding movement between each terminal, and isolates said power supply circuit by sliding movement of said shaft from the initial position where each said terminal is set in a connected state with each other to the isolated position where each said terminal is set in a released state with each other. Further, the power source breaker according to the present invention is characterized by comprising: a release spring which provides the shaft with pushing force for sliding movement of said shaft from said initial position to said isolated position; a lock which is assembled rotatable around the central axis of a rotary axle along a plane perpendicular to the sliding direction of said shaft, and can constrain the shaft, pushed by said release spring, at the initial position by means of changing a rotation angle of the rotary axle, and also can make the shaft movable to said isolated position by means of releasing the constraint.
According to the present invention, since only by changing a rotation angle of the rotary axle on the lock which is assembled rotatable around the central axis of the rotary axle along the plane perpendicular to the sliding direction of said shaft, both constraining the shaft, pushed by said release spring, at the initial position where a pair of the terminals intervened in a power supply circuit is in the connected state with each other and moving the shaft to the isolated position where a pair of the terminals intervened in the power supply circuit is set in the released state, the power source breaker can be constructed with a torque generator such as a motor and the like which is simpler and smaller than a linearly driven solenoid. Moreover, since a rotary motion is utilized, whenever any other impulse may be applied onto the power source breaker than those in case of something unusual such as short circuiting of a wire harness, collision of vehicles, the power source breaker is generally not liable to be affected by an impulse which is a composition of linear mechanical vibrations and the shaft can be maintained at a constrained state, and it can be avoided that the lock may be released by virtue of this kind of impulse resulting in sliding movement of the shaft.
Another embodiment of the present invention is characterized by forming a tapered face on a portion of the lock for contact-stopping the shaft from moving. As regards the utilization of the lock wherein the tapered face is formed on the portion for contact-stopping the shaft (hereinafter, refer to the contact-stop portion) from moving in order to avoid promptly the interference with the shaft at an instant isolation movement, it is useful to miniaturize the power source breaker through designing a radius of gyration to be as small as possible.
According to another embodiment of the present invention, it is further characterized by the fact that the lock changes its rotation angle following a rotary movement of a rotary actuator, and a disk is assembled concentrically with a driving shaft of the rotary actuator, providing a protrusion on the periphery of the disk concerned, and a portion of the lock to be linked to said protrusion is released from the protrusion after completion of the isolation movement. According to the invention, whenever any other impulse may be applied onto the power source breaker than those in case of abnormalities such as short circuiting of a wire harness, collision of vehicles, the shaft can be maintained at the constrained state because the lock is actuated by torque, and it can be avoided that the lock may be released by virtue of this kind of impulse resulting in sliding movement of the shaft. Further, since the portion of the lock to be linked (hereinafter, refer to the link portion) to the protrusion of the disk assembled onto a geared motor is released from the protrusion after completion of the isolation movement, the shaft can be immediately reset at the initial position after completion of the isolation movement. Therefore, it is easy to make the power supply circuit return to an electrically closed state. Another embodiment of the present invention is characterized by disposing the lock eccentrically with said rotary axle in such a relation as the contact-stop portion of the lock may be larger than the other portion.
According to the present invention, with regard to the utilization of the lock which is disposed eccentrically with the rotary axle in such a relation as the contact-stop portion of the lock may be larger than the other portion, that is useful to miniaturize the power source breaker through designing a radius of gyration to be as small as possible.